It is known to provide articles of various types with a frame-shaped sealing profile of polymer, and in particular of elastomer, by extruding a profiled member of extrudable material directly onto the article. For automobile panes, in particular, processes of this class are widely used. To do this, extrudable systems are used which polymerize or cross-link, such as systems of humidity-hardening polyurethane, and also thermoplastic elastomers. Processes of this class are described in detail for example, in European Patents EP-A-0 421 833 and EP-A-0 524 092.
When a profiled frame, closed on itself, is applied by extrusion onto the surface of an object, it is necessary to post-shape or finally shape the junction between the start of the extruded profiled cord and its end, because an accumulation of the viscous material inevitably takes place with a more or less undefined form. For post-shaping this undefined transition zone, various processes and devices are known.
According to a method known from DE 40 25 166 A1, in which a profiled polyurethane cord is applied by extrusion onto a surface, the extruded cord is allowed to harden, a portion of the cord is removed from the position of the transition, and a corresponding portion of a profiled cord which has already hardened is glued at this position.
According to another method known from EP-A-524 060, a portion of the profile is also removed by mechanical means after it has hardened. Then a calibrated mould, covering the two contiguous ends of the frame-shaped profile, is placed at this position and a polymer that hardens relatively rapidly is injected into the mould and hardened to complete the profiled frame.
In addition, it is known to post-shape the profiled frame at the transition position during the extrusion and before the polymer has hardened, by using tools that shape by compression. A tool known from EP-B-421 833 is composed of a lower plate, in which a moulding cavity is formed and which can be in one or more pieces. The upper compression plate is lowered onto the lower moulding plate, where it forms the profile.
A process of this type, well known and described in DE 90 115 73 U1, serves for the post-shaping of a profiled cord constituted of a reactive system based upon polyurethane and extruded and applied onto a pane. In this process, the mould is composed of a device equipped with two jaws, which is guided in the open position from the outside above the peripheral part of the pane, equipped with the profiled cord. The pivoting axis of the two jaws is disposed outside the object. After the positioning of the device of the mould, in which the surface of the pane in relation to the profiled cord is disposed in a corresponding recess of the one of the jaws, the other jaw, which imprints its form onto the cord, pivots around the pivot axis and is pressed onto the cord.
In the case in which the cord possesses a groove with an undercut or back-cut, the above-mentioned processes for post-shaping before hardening are not suitable. The same is true when the wall of the groove is fluted on one side where the wall closes in. These two arrangements are common when, as in the document EP-B-258 128, a reversible fixing is desired of an automobile pane into an opening of the bodywork. In this case, the engagement between the positioning mastic and the profiled frame is made without gluing solely on account of the shape of the groove of the profiled frame onto which the mastic engages. But by the same token, if a traditional die is used for shaping the groove, it will be impossible to remove it before hardening without definitively deforming the profile.